All females, individuals not facing depression and those with low vitamin D levels would also benefit from the supplementation.
The analysis, titled “Effect of vitamin D supplementation on the incidence and prognosis of depression: An updated meta-analysis based on randomized controlled trials”, was published in the journal Frontiers in Public Health.
“Insufficient and deficiency of vitamin D are related to neurological disorders. Also, the correlation between low-level vitamin D and depression has been proved. Therefore, implementing vitamin D in antidepression treatment has raised awareness among healthcare professionals.
“However, in two subsequent meta-analyses, there was no evidence that vitamin D supplementation was always desirable in relieving depressive symptoms in people with different health problems.
“Based on the shortcomings above and in the hope of providing some guiding significance for clinical application, we intend to review the relevant randomized controlled trials (RCTs) and conduct an updated meta-analysis to investigate the effect of vitamin D supplementation on the incidence and prognosis of depression,” said the scientists.
The team scoured various academic databases for relevant RCTs according to the inclusion and exclusion criteria. Out of a possible 3,432 relevant studies, a total of 29 eligible studies were analysed – 18 discussed the correlation between vitamin D and the incidence of depression and another 11 featured the correlation between vitamin D and the development of depression.
In the 29 studies, there were 4,504 participants and aged between 13 to 85. They consumed vitamin D doses ranging from 200 to more than 10,000 IU daily. They were located in various parts of Europe, Asia and Oceania.
The studies chosen were congruent with past research, such as the meta-analyses done by Shaffer J. A. et al. (2014), Vellekkatt F. et al. (2019) and Cheng Y. C. et al. (2020), in whereby vitamin D supplementation was found to be associated with a decrease in the occurrence of depression and an improvement in its treatment.
Previous meta-analyses, like Anglin R. E. S. et al. (2013) and Ju S. Y. et al. (2013), also found that patients with low vitamin D levels could benefit from supplementation in the prevention and treatment of depression. Hence, these results might be supportive in considering the effectiveness of vitamin D supplementation to lower the risk and improve the treatment of depression.
Upon further analysis of the gender subgroup, vitamin D supplements had significantly alleviated depression scores in all females, regardless of whether they were depressed. For example, Alghamdi S. et al. (2020) showed female patients with depressive symptoms improved significantly after vitamin D supplementation than males.
In terms of dosage, the threshold was 2,800 IU daily as higher doses than that were found to be beneficial for prevention and treatment. Lower doses were ineffective. However, due to the limited number of studies on low-dose supplementation, the results should be interpreted with caution.
The duration of the intervention was found to be best at eight weeks to trigger a response from the vitamin. A response was also triggered when the intervention was longer than eight weeks. Hence, the phenomenon could also be interpreted by the fact that the mean vitamin D levels in depressed people are more likely to be lower than that in non-depressed people, making depressed individuals more sensitive to vitamin D administration.
In conclusion, this meta-analysis demonstrated that vitamin D positively impacts both the decreased incidence of depression and a better prognosis of depression. Whether suffering from depression or not, individuals with low vitamin D levels and females are also most likely to benefit from vitamin D supplementation.
“A daily supplementary dose of 2,800 IU and an intervention duration of 8 weeks are considered as the point that may cause the observational effect of vitamin D. Our results also reveal that vitamin D supplementation works well in both prevention and treatment in normal-weight people, whereas only in treatment not prevention for those who are overweight,” concluded the scientists.
Source: Frontiers in Public Health
“Effect of vitamin D supplementation on the incidence and prognosis of depression: An updated meta-analysis based on randomized controlled trials”
Authors: Xie Fei et al.
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